Of patients with advanced non-small-cell lung cancer (NSCLC), 5-10% have interstitial pneumonia (IP) at the time of diagnosis. To avoid fatal acute exacerbations of pre-existing IP, appropriate patient selection and low-risk treatment choices are warranted. Risk factors for acute exacerbation of pre-existing IP with cytotoxic drugs include honeycomb lungs on computed tomography (CT) and low forced vital capacity, but risk factors with immune checkpoint inhibitors (ICIs) have not been fully investigated. For advanced or recurrent NSCLC with comorbid IP, carboplatin plus nanoparticle albumin-bound paclitaxel is the standard of care for first-line treatment, but second-line or later treatment has not been established. ICI holds great promise for long-term survival, but many challenges remain, including safety and appropriate patient selection. Since the indications for pharmacotherapy and radiotherapy for NSCLC with comorbid IP are quite limited, surgical resection should be considered as much as possible for patients with operable stages. A scoring system has been reported to predict the risk of postoperative acute exacerbation of pre-existing IP, but perioperative treatment has not been established. In the future, it is necessary to accumulate more cases and conduct further research, not only in Japan but also worldwide.
Keywords: acute exacerbation; cytotoxic drug; idiopathic pulmonary fibrosis; immune checkpoint inhibitor; interstitial pneumonia; non-small-cell lung cancer; perioperative treatment; pneumonitis; radiation therapy; surgery.